1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
4 Free Software Foundation, Inc.
6 Contributed by Mark Kettenis.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "dwarf2expr.h"
27 #include "frame-base.h"
28 #include "frame-unwind.h"
36 #include "gdb_assert.h"
37 #include "gdb_string.h"
39 #include "complaints.h"
40 #include "dwarf2-frame.h"
42 #include "dwarf2loc.h"
43 #include "exceptions.h"
47 /* Call Frame Information (CFI). */
49 /* Common Information Entry (CIE). */
53 /* Computation Unit for this CIE. */
54 struct comp_unit *unit;
56 /* Offset into the .debug_frame section where this CIE was found.
57 Used to identify this CIE. */
60 /* Constant that is factored out of all advance location
62 ULONGEST code_alignment_factor;
64 /* Constants that is factored out of all offset instructions. */
65 LONGEST data_alignment_factor;
67 /* Return address column. */
68 ULONGEST return_address_register;
70 /* Instruction sequence to initialize a register set. */
71 gdb_byte *initial_instructions;
74 /* Saved augmentation, in case it's needed later. */
77 /* Encoding of addresses. */
80 /* Target address size in bytes. */
83 /* Target pointer size in bytes. */
86 /* True if a 'z' augmentation existed. */
87 unsigned char saw_z_augmentation;
89 /* True if an 'S' augmentation existed. */
90 unsigned char signal_frame;
92 /* The version recorded in the CIE. */
93 unsigned char version;
95 /* The segment size. */
96 unsigned char segment_size;
99 struct dwarf2_cie_table
102 struct dwarf2_cie **entries;
105 /* Frame Description Entry (FDE). */
109 /* CIE for this FDE. */
110 struct dwarf2_cie *cie;
112 /* First location associated with this FDE. */
113 CORE_ADDR initial_location;
115 /* Number of bytes of program instructions described by this FDE. */
116 CORE_ADDR address_range;
118 /* Instruction sequence. */
119 gdb_byte *instructions;
122 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
124 unsigned char eh_frame_p;
127 struct dwarf2_fde_table
130 struct dwarf2_fde **entries;
133 /* A minimal decoding of DWARF2 compilation units. We only decode
134 what's needed to get to the call frame information. */
138 /* Keep the bfd convenient. */
141 struct objfile *objfile;
143 /* Pointer to the .debug_frame section loaded into memory. */
144 gdb_byte *dwarf_frame_buffer;
146 /* Length of the loaded .debug_frame section. */
147 bfd_size_type dwarf_frame_size;
149 /* Pointer to the .debug_frame section. */
150 asection *dwarf_frame_section;
152 /* Base for DW_EH_PE_datarel encodings. */
155 /* Base for DW_EH_PE_textrel encodings. */
159 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
160 CORE_ADDR *out_offset);
162 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
165 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
166 int ptr_len, const gdb_byte *buf,
167 unsigned int *bytes_read_ptr,
168 CORE_ADDR func_base);
171 /* Structure describing a frame state. */
173 struct dwarf2_frame_state
175 /* Each register save state can be described in terms of a CFA slot,
176 another register, or a location expression. */
177 struct dwarf2_frame_state_reg_info
179 struct dwarf2_frame_state_reg *reg;
189 const gdb_byte *cfa_exp;
191 /* Used to implement DW_CFA_remember_state. */
192 struct dwarf2_frame_state_reg_info *prev;
195 /* The PC described by the current frame state. */
198 /* Initial register set from the CIE.
199 Used to implement DW_CFA_restore. */
200 struct dwarf2_frame_state_reg_info initial;
202 /* The information we care about from the CIE. */
205 ULONGEST retaddr_column;
207 /* Flags for known producer quirks. */
209 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
210 and DW_CFA_def_cfa_offset takes a factored offset. */
211 int armcc_cfa_offsets_sf;
213 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
214 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
215 int armcc_cfa_offsets_reversed;
218 /* Store the length the expression for the CFA in the `cfa_reg' field,
219 which is unused in that case. */
220 #define cfa_exp_len cfa_reg
222 /* Assert that the register set RS is large enough to store gdbarch_num_regs
223 columns. If necessary, enlarge the register set. */
226 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
229 size_t size = sizeof (struct dwarf2_frame_state_reg);
231 if (num_regs <= rs->num_regs)
234 rs->reg = (struct dwarf2_frame_state_reg *)
235 xrealloc (rs->reg, num_regs * size);
237 /* Initialize newly allocated registers. */
238 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
239 rs->num_regs = num_regs;
242 /* Copy the register columns in register set RS into newly allocated
243 memory and return a pointer to this newly created copy. */
245 static struct dwarf2_frame_state_reg *
246 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
248 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
249 struct dwarf2_frame_state_reg *reg;
251 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
252 memcpy (reg, rs->reg, size);
257 /* Release the memory allocated to register set RS. */
260 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
264 dwarf2_frame_state_free_regs (rs->prev);
271 /* Release the memory allocated to the frame state FS. */
274 dwarf2_frame_state_free (void *p)
276 struct dwarf2_frame_state *fs = p;
278 dwarf2_frame_state_free_regs (fs->initial.prev);
279 dwarf2_frame_state_free_regs (fs->regs.prev);
280 xfree (fs->initial.reg);
281 xfree (fs->regs.reg);
286 /* Helper functions for execute_stack_op. */
289 read_reg (void *baton, int reg)
291 struct frame_info *this_frame = (struct frame_info *) baton;
292 struct gdbarch *gdbarch = get_frame_arch (this_frame);
296 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
298 buf = alloca (register_size (gdbarch, regnum));
299 get_frame_register (this_frame, regnum, buf);
301 /* Convert the register to an integer. This returns a LONGEST
302 rather than a CORE_ADDR, but unpack_pointer does the same thing
303 under the covers, and this makes more sense for non-pointer
304 registers. Maybe read_reg and the associated interfaces should
305 deal with "struct value" instead of CORE_ADDR. */
306 return unpack_long (register_type (gdbarch, regnum), buf);
310 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
312 read_memory (addr, buf, len);
315 /* Execute the required actions for both the DW_CFA_restore and
316 DW_CFA_restore_extended instructions. */
318 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
319 struct dwarf2_frame_state *fs, int eh_frame_p)
323 gdb_assert (fs->initial.reg);
324 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
325 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
327 /* Check if this register was explicitly initialized in the
328 CIE initial instructions. If not, default the rule to
330 if (reg < fs->initial.num_regs)
331 fs->regs.reg[reg] = fs->initial.reg[reg];
333 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
335 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
336 complaint (&symfile_complaints, _("\
337 incomplete CFI data; DW_CFA_restore unspecified\n\
338 register %s (#%d) at %s"),
339 gdbarch_register_name
340 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
341 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
342 paddress (gdbarch, fs->pc));
345 /* Virtual method table for execute_stack_op below. */
347 static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
351 ctx_no_get_frame_base,
352 ctx_no_get_frame_cfa,
354 ctx_no_get_tls_address,
356 ctx_no_get_base_type,
357 ctx_no_push_dwarf_reg_entry_value
361 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
362 CORE_ADDR offset, struct frame_info *this_frame,
363 CORE_ADDR initial, int initial_in_stack_memory)
365 struct dwarf_expr_context *ctx;
367 struct cleanup *old_chain;
369 ctx = new_dwarf_expr_context ();
370 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
371 make_cleanup_value_free_to_mark (value_mark ());
373 ctx->gdbarch = get_frame_arch (this_frame);
374 ctx->addr_size = addr_size;
375 ctx->ref_addr_size = -1;
376 ctx->offset = offset;
377 ctx->baton = this_frame;
378 ctx->funcs = &dwarf2_frame_ctx_funcs;
380 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
381 dwarf_expr_eval (ctx, exp, len);
383 if (ctx->location == DWARF_VALUE_MEMORY)
384 result = dwarf_expr_fetch_address (ctx, 0);
385 else if (ctx->location == DWARF_VALUE_REGISTER)
386 result = read_reg (this_frame, value_as_long (dwarf_expr_fetch (ctx, 0)));
389 /* This is actually invalid DWARF, but if we ever do run across
390 it somehow, we might as well support it. So, instead, report
391 it as unimplemented. */
393 Not implemented: computing unwound register using explicit value operator"));
396 do_cleanups (old_chain);
403 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
404 const gdb_byte *insn_end, struct gdbarch *gdbarch,
405 CORE_ADDR pc, struct dwarf2_frame_state *fs)
407 int eh_frame_p = fde->eh_frame_p;
409 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
411 while (insn_ptr < insn_end && fs->pc <= pc)
413 gdb_byte insn = *insn_ptr++;
417 if ((insn & 0xc0) == DW_CFA_advance_loc)
418 fs->pc += (insn & 0x3f) * fs->code_align;
419 else if ((insn & 0xc0) == DW_CFA_offset)
422 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
423 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
424 offset = utmp * fs->data_align;
425 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
426 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
427 fs->regs.reg[reg].loc.offset = offset;
429 else if ((insn & 0xc0) == DW_CFA_restore)
432 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
439 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
440 fde->cie->ptr_size, insn_ptr,
441 &bytes_read, fde->initial_location);
442 /* Apply the objfile offset for relocatable objects. */
443 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
444 SECT_OFF_TEXT (fde->cie->unit->objfile));
445 insn_ptr += bytes_read;
448 case DW_CFA_advance_loc1:
449 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
450 fs->pc += utmp * fs->code_align;
453 case DW_CFA_advance_loc2:
454 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
455 fs->pc += utmp * fs->code_align;
458 case DW_CFA_advance_loc4:
459 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
460 fs->pc += utmp * fs->code_align;
464 case DW_CFA_offset_extended:
465 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
466 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
467 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
468 offset = utmp * fs->data_align;
469 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
470 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
471 fs->regs.reg[reg].loc.offset = offset;
474 case DW_CFA_restore_extended:
475 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
476 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
479 case DW_CFA_undefined:
480 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
481 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
482 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
483 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
486 case DW_CFA_same_value:
487 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
488 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
489 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
490 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
493 case DW_CFA_register:
494 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
495 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
496 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
497 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
498 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
499 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
500 fs->regs.reg[reg].loc.reg = utmp;
503 case DW_CFA_remember_state:
505 struct dwarf2_frame_state_reg_info *new_rs;
507 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
509 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
510 fs->regs.prev = new_rs;
514 case DW_CFA_restore_state:
516 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
520 complaint (&symfile_complaints, _("\
521 bad CFI data; mismatched DW_CFA_restore_state at %s"),
522 paddress (gdbarch, fs->pc));
526 xfree (fs->regs.reg);
534 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
535 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
537 if (fs->armcc_cfa_offsets_sf)
538 utmp *= fs->data_align;
540 fs->regs.cfa_offset = utmp;
541 fs->regs.cfa_how = CFA_REG_OFFSET;
544 case DW_CFA_def_cfa_register:
545 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
546 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
549 fs->regs.cfa_how = CFA_REG_OFFSET;
552 case DW_CFA_def_cfa_offset:
553 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
555 if (fs->armcc_cfa_offsets_sf)
556 utmp *= fs->data_align;
558 fs->regs.cfa_offset = utmp;
559 /* cfa_how deliberately not set. */
565 case DW_CFA_def_cfa_expression:
566 insn_ptr = read_uleb128 (insn_ptr, insn_end,
567 &fs->regs.cfa_exp_len);
568 fs->regs.cfa_exp = insn_ptr;
569 fs->regs.cfa_how = CFA_EXP;
570 insn_ptr += fs->regs.cfa_exp_len;
573 case DW_CFA_expression:
574 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
575 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
576 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
577 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
578 fs->regs.reg[reg].loc.exp = insn_ptr;
579 fs->regs.reg[reg].exp_len = utmp;
580 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
584 case DW_CFA_offset_extended_sf:
585 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
586 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
587 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
588 offset *= fs->data_align;
589 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
590 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
591 fs->regs.reg[reg].loc.offset = offset;
594 case DW_CFA_val_offset:
595 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
596 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
597 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
598 offset = utmp * fs->data_align;
599 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
600 fs->regs.reg[reg].loc.offset = offset;
603 case DW_CFA_val_offset_sf:
604 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
605 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
606 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
607 offset *= fs->data_align;
608 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
609 fs->regs.reg[reg].loc.offset = offset;
612 case DW_CFA_val_expression:
613 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
614 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
615 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
616 fs->regs.reg[reg].loc.exp = insn_ptr;
617 fs->regs.reg[reg].exp_len = utmp;
618 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
622 case DW_CFA_def_cfa_sf:
623 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
624 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
627 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
628 fs->regs.cfa_offset = offset * fs->data_align;
629 fs->regs.cfa_how = CFA_REG_OFFSET;
632 case DW_CFA_def_cfa_offset_sf:
633 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
634 fs->regs.cfa_offset = offset * fs->data_align;
635 /* cfa_how deliberately not set. */
638 case DW_CFA_GNU_window_save:
639 /* This is SPARC-specific code, and contains hard-coded
640 constants for the register numbering scheme used by
641 GCC. Rather than having a architecture-specific
642 operation that's only ever used by a single
643 architecture, we provide the implementation here.
644 Incidentally that's what GCC does too in its
647 int size = register_size (gdbarch, 0);
649 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
650 for (reg = 8; reg < 16; reg++)
652 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
653 fs->regs.reg[reg].loc.reg = reg + 16;
655 for (reg = 16; reg < 32; reg++)
657 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
658 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
663 case DW_CFA_GNU_args_size:
665 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
668 case DW_CFA_GNU_negative_offset_extended:
669 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
670 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
671 insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
672 offset *= fs->data_align;
673 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
674 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
675 fs->regs.reg[reg].loc.offset = -offset;
679 internal_error (__FILE__, __LINE__,
680 _("Unknown CFI encountered."));
685 /* Don't allow remember/restore between CIE and FDE programs. */
686 dwarf2_frame_state_free_regs (fs->regs.prev);
687 fs->regs.prev = NULL;
691 /* Architecture-specific operations. */
693 /* Per-architecture data key. */
694 static struct gdbarch_data *dwarf2_frame_data;
696 struct dwarf2_frame_ops
698 /* Pre-initialize the register state REG for register REGNUM. */
699 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
700 struct frame_info *);
702 /* Check whether the THIS_FRAME is a signal trampoline. */
703 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
705 /* Convert .eh_frame register number to DWARF register number, or
706 adjust .debug_frame register number. */
707 int (*adjust_regnum) (struct gdbarch *, int, int);
710 /* Default architecture-specific register state initialization
714 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
715 struct dwarf2_frame_state_reg *reg,
716 struct frame_info *this_frame)
718 /* If we have a register that acts as a program counter, mark it as
719 a destination for the return address. If we have a register that
720 serves as the stack pointer, arrange for it to be filled with the
721 call frame address (CFA). The other registers are marked as
724 We copy the return address to the program counter, since many
725 parts in GDB assume that it is possible to get the return address
726 by unwinding the program counter register. However, on ISA's
727 with a dedicated return address register, the CFI usually only
728 contains information to unwind that return address register.
730 The reason we're treating the stack pointer special here is
731 because in many cases GCC doesn't emit CFI for the stack pointer
732 and implicitly assumes that it is equal to the CFA. This makes
733 some sense since the DWARF specification (version 3, draft 8,
736 "Typically, the CFA is defined to be the value of the stack
737 pointer at the call site in the previous frame (which may be
738 different from its value on entry to the current frame)."
740 However, this isn't true for all platforms supported by GCC
741 (e.g. IBM S/390 and zSeries). Those architectures should provide
742 their own architecture-specific initialization function. */
744 if (regnum == gdbarch_pc_regnum (gdbarch))
745 reg->how = DWARF2_FRAME_REG_RA;
746 else if (regnum == gdbarch_sp_regnum (gdbarch))
747 reg->how = DWARF2_FRAME_REG_CFA;
750 /* Return a default for the architecture-specific operations. */
753 dwarf2_frame_init (struct obstack *obstack)
755 struct dwarf2_frame_ops *ops;
757 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
758 ops->init_reg = dwarf2_frame_default_init_reg;
762 /* Set the architecture-specific register state initialization
763 function for GDBARCH to INIT_REG. */
766 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
767 void (*init_reg) (struct gdbarch *, int,
768 struct dwarf2_frame_state_reg *,
769 struct frame_info *))
771 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
773 ops->init_reg = init_reg;
776 /* Pre-initialize the register state REG for register REGNUM. */
779 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
780 struct dwarf2_frame_state_reg *reg,
781 struct frame_info *this_frame)
783 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
785 ops->init_reg (gdbarch, regnum, reg, this_frame);
788 /* Set the architecture-specific signal trampoline recognition
789 function for GDBARCH to SIGNAL_FRAME_P. */
792 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
793 int (*signal_frame_p) (struct gdbarch *,
794 struct frame_info *))
796 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
798 ops->signal_frame_p = signal_frame_p;
801 /* Query the architecture-specific signal frame recognizer for
805 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
806 struct frame_info *this_frame)
808 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
810 if (ops->signal_frame_p == NULL)
812 return ops->signal_frame_p (gdbarch, this_frame);
815 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
819 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
820 int (*adjust_regnum) (struct gdbarch *,
823 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
825 ops->adjust_regnum = adjust_regnum;
828 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
832 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
833 int regnum, int eh_frame_p)
835 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
837 if (ops->adjust_regnum == NULL)
839 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
843 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
844 struct dwarf2_fde *fde)
848 s = find_pc_symtab (fs->pc);
852 if (producer_is_realview (s->producer))
854 if (fde->cie->version == 1)
855 fs->armcc_cfa_offsets_sf = 1;
857 if (fde->cie->version == 1)
858 fs->armcc_cfa_offsets_reversed = 1;
860 /* The reversed offset problem is present in some compilers
861 using DWARF3, but it was eventually fixed. Check the ARM
862 defined augmentations, which are in the format "armcc" followed
863 by a list of one-character options. The "+" option means
864 this problem is fixed (no quirk needed). If the armcc
865 augmentation is missing, the quirk is needed. */
866 if (fde->cie->version == 3
867 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
868 || strchr (fde->cie->augmentation + 5, '+') == NULL))
869 fs->armcc_cfa_offsets_reversed = 1;
877 dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
878 struct gdbarch *gdbarch,
880 struct dwarf2_per_cu_data *data)
882 const int num_regs = gdbarch_num_regs (gdbarch)
883 + gdbarch_num_pseudo_regs (gdbarch);
884 struct dwarf2_fde *fde;
885 CORE_ADDR text_offset, cfa;
886 struct dwarf2_frame_state fs;
889 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
893 /* Find the correct FDE. */
894 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
896 error (_("Could not compute CFA; needed to translate this expression"));
898 /* Extract any interesting information from the CIE. */
899 fs.data_align = fde->cie->data_alignment_factor;
900 fs.code_align = fde->cie->code_alignment_factor;
901 fs.retaddr_column = fde->cie->return_address_register;
902 addr_size = fde->cie->addr_size;
904 /* Check for "quirks" - known bugs in producers. */
905 dwarf2_frame_find_quirks (&fs, fde);
907 /* First decode all the insns in the CIE. */
908 execute_cfa_program (fde, fde->cie->initial_instructions,
909 fde->cie->end, gdbarch, pc, &fs);
911 /* Save the initialized register set. */
912 fs.initial = fs.regs;
913 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
915 /* Then decode the insns in the FDE up to our target PC. */
916 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
918 /* Calculate the CFA. */
919 switch (fs.regs.cfa_how)
923 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
926 error (_("Unable to access DWARF register number %d"),
927 (int) fs.regs.cfa_reg); /* FIXME */
928 ax_reg (expr, regnum);
930 if (fs.regs.cfa_offset != 0)
932 if (fs.armcc_cfa_offsets_reversed)
933 ax_const_l (expr, -fs.regs.cfa_offset);
935 ax_const_l (expr, fs.regs.cfa_offset);
936 ax_simple (expr, aop_add);
942 ax_const_l (expr, text_offset);
943 dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
945 fs.regs.cfa_exp + fs.regs.cfa_exp_len,
950 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
955 struct dwarf2_frame_cache
957 /* DWARF Call Frame Address. */
960 /* Set if the return address column was marked as unavailable
961 (required non-collected memory or registers to compute). */
962 int unavailable_retaddr;
964 /* Set if the return address column was marked as undefined. */
965 int undefined_retaddr;
967 /* Saved registers, indexed by GDB register number, not by DWARF
969 struct dwarf2_frame_state_reg *reg;
971 /* Return address register. */
972 struct dwarf2_frame_state_reg retaddr_reg;
974 /* Target address size in bytes. */
977 /* The .text offset. */
978 CORE_ADDR text_offset;
981 static struct dwarf2_frame_cache *
982 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
984 struct cleanup *old_chain;
985 struct gdbarch *gdbarch = get_frame_arch (this_frame);
986 const int num_regs = gdbarch_num_regs (gdbarch)
987 + gdbarch_num_pseudo_regs (gdbarch);
988 struct dwarf2_frame_cache *cache;
989 struct dwarf2_frame_state *fs;
990 struct dwarf2_fde *fde;
991 volatile struct gdb_exception ex;
996 /* Allocate a new cache. */
997 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
998 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
1001 /* Allocate and initialize the frame state. */
1002 fs = XZALLOC (struct dwarf2_frame_state);
1003 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1007 Note that if the next frame is never supposed to return (i.e. a call
1008 to abort), the compiler might optimize away the instruction at
1009 its return address. As a result the return address will
1010 point at some random instruction, and the CFI for that
1011 instruction is probably worthless to us. GCC's unwinder solves
1012 this problem by substracting 1 from the return address to get an
1013 address in the middle of a presumed call instruction (or the
1014 instruction in the associated delay slot). This should only be
1015 done for "normal" frames and not for resume-type frames (signal
1016 handlers, sentinel frames, dummy frames). The function
1017 get_frame_address_in_block does just this. It's not clear how
1018 reliable the method is though; there is the potential for the
1019 register state pre-call being different to that on return. */
1020 fs->pc = get_frame_address_in_block (this_frame);
1022 /* Find the correct FDE. */
1023 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
1024 gdb_assert (fde != NULL);
1026 /* Extract any interesting information from the CIE. */
1027 fs->data_align = fde->cie->data_alignment_factor;
1028 fs->code_align = fde->cie->code_alignment_factor;
1029 fs->retaddr_column = fde->cie->return_address_register;
1030 cache->addr_size = fde->cie->addr_size;
1032 /* Check for "quirks" - known bugs in producers. */
1033 dwarf2_frame_find_quirks (fs, fde);
1035 /* First decode all the insns in the CIE. */
1036 execute_cfa_program (fde, fde->cie->initial_instructions,
1037 fde->cie->end, gdbarch, get_frame_pc (this_frame), fs);
1039 /* Save the initialized register set. */
1040 fs->initial = fs->regs;
1041 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1043 /* Then decode the insns in the FDE up to our target PC. */
1044 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1045 get_frame_pc (this_frame), fs);
1047 TRY_CATCH (ex, RETURN_MASK_ERROR)
1049 /* Calculate the CFA. */
1050 switch (fs->regs.cfa_how)
1052 case CFA_REG_OFFSET:
1053 cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
1054 if (fs->armcc_cfa_offsets_reversed)
1055 cache->cfa -= fs->regs.cfa_offset;
1057 cache->cfa += fs->regs.cfa_offset;
1062 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1063 cache->addr_size, cache->text_offset,
1068 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1073 if (ex.error == NOT_AVAILABLE_ERROR)
1075 cache->unavailable_retaddr = 1;
1079 throw_exception (ex);
1082 /* Initialize the register state. */
1086 for (regnum = 0; regnum < num_regs; regnum++)
1087 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1090 /* Go through the DWARF2 CFI generated table and save its register
1091 location information in the cache. Note that we don't skip the
1092 return address column; it's perfectly all right for it to
1093 correspond to a real register. If it doesn't correspond to a
1094 real register, or if we shouldn't treat it as such,
1095 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1096 the range [0, gdbarch_num_regs). */
1098 int column; /* CFI speak for "register number". */
1100 for (column = 0; column < fs->regs.num_regs; column++)
1102 /* Use the GDB register number as the destination index. */
1103 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1105 /* If there's no corresponding GDB register, ignore it. */
1106 if (regnum < 0 || regnum >= num_regs)
1109 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1110 of all debug info registers. If it doesn't, complain (but
1111 not too loudly). It turns out that GCC assumes that an
1112 unspecified register implies "same value" when CFI (draft
1113 7) specifies nothing at all. Such a register could equally
1114 be interpreted as "undefined". Also note that this check
1115 isn't sufficient; it only checks that all registers in the
1116 range [0 .. max column] are specified, and won't detect
1117 problems when a debug info register falls outside of the
1118 table. We need a way of iterating through all the valid
1119 DWARF2 register numbers. */
1120 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1122 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1123 complaint (&symfile_complaints, _("\
1124 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1125 gdbarch_register_name (gdbarch, regnum),
1126 paddress (gdbarch, fs->pc));
1129 cache->reg[regnum] = fs->regs.reg[column];
1133 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1134 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1138 for (regnum = 0; regnum < num_regs; regnum++)
1140 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1141 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1143 struct dwarf2_frame_state_reg *retaddr_reg =
1144 &fs->regs.reg[fs->retaddr_column];
1146 /* It seems rather bizarre to specify an "empty" column as
1147 the return adress column. However, this is exactly
1148 what GCC does on some targets. It turns out that GCC
1149 assumes that the return address can be found in the
1150 register corresponding to the return address column.
1151 Incidentally, that's how we should treat a return
1152 address column specifying "same value" too. */
1153 if (fs->retaddr_column < fs->regs.num_regs
1154 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1155 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1157 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1158 cache->reg[regnum] = *retaddr_reg;
1160 cache->retaddr_reg = *retaddr_reg;
1164 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1166 cache->reg[regnum].loc.reg = fs->retaddr_column;
1167 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1171 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1172 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1179 if (fs->retaddr_column < fs->regs.num_regs
1180 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1181 cache->undefined_retaddr = 1;
1183 do_cleanups (old_chain);
1188 static enum unwind_stop_reason
1189 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1192 struct dwarf2_frame_cache *cache
1193 = dwarf2_frame_cache (this_frame, this_cache);
1195 if (cache->unavailable_retaddr)
1196 return UNWIND_UNAVAILABLE;
1198 if (cache->undefined_retaddr)
1199 return UNWIND_OUTERMOST;
1201 return UNWIND_NO_REASON;
1205 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1206 struct frame_id *this_id)
1208 struct dwarf2_frame_cache *cache =
1209 dwarf2_frame_cache (this_frame, this_cache);
1211 if (cache->unavailable_retaddr)
1214 if (cache->undefined_retaddr)
1217 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1220 static struct value *
1221 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1224 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1225 struct dwarf2_frame_cache *cache =
1226 dwarf2_frame_cache (this_frame, this_cache);
1230 switch (cache->reg[regnum].how)
1232 case DWARF2_FRAME_REG_UNDEFINED:
1233 /* If CFI explicitly specified that the value isn't defined,
1234 mark it as optimized away; the value isn't available. */
1235 return frame_unwind_got_optimized (this_frame, regnum);
1237 case DWARF2_FRAME_REG_SAVED_OFFSET:
1238 addr = cache->cfa + cache->reg[regnum].loc.offset;
1239 return frame_unwind_got_memory (this_frame, regnum, addr);
1241 case DWARF2_FRAME_REG_SAVED_REG:
1243 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1244 return frame_unwind_got_register (this_frame, regnum, realnum);
1246 case DWARF2_FRAME_REG_SAVED_EXP:
1247 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1248 cache->reg[regnum].exp_len,
1249 cache->addr_size, cache->text_offset,
1250 this_frame, cache->cfa, 1);
1251 return frame_unwind_got_memory (this_frame, regnum, addr);
1253 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1254 addr = cache->cfa + cache->reg[regnum].loc.offset;
1255 return frame_unwind_got_constant (this_frame, regnum, addr);
1257 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1258 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1259 cache->reg[regnum].exp_len,
1260 cache->addr_size, cache->text_offset,
1261 this_frame, cache->cfa, 1);
1262 return frame_unwind_got_constant (this_frame, regnum, addr);
1264 case DWARF2_FRAME_REG_UNSPECIFIED:
1265 /* GCC, in its infinite wisdom decided to not provide unwind
1266 information for registers that are "same value". Since
1267 DWARF2 (3 draft 7) doesn't define such behavior, said
1268 registers are actually undefined (which is different to CFI
1269 "undefined"). Code above issues a complaint about this.
1270 Here just fudge the books, assume GCC, and that the value is
1271 more inner on the stack. */
1272 return frame_unwind_got_register (this_frame, regnum, regnum);
1274 case DWARF2_FRAME_REG_SAME_VALUE:
1275 return frame_unwind_got_register (this_frame, regnum, regnum);
1277 case DWARF2_FRAME_REG_CFA:
1278 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1280 case DWARF2_FRAME_REG_CFA_OFFSET:
1281 addr = cache->cfa + cache->reg[regnum].loc.offset;
1282 return frame_unwind_got_address (this_frame, regnum, addr);
1284 case DWARF2_FRAME_REG_RA_OFFSET:
1285 addr = cache->reg[regnum].loc.offset;
1286 regnum = gdbarch_dwarf2_reg_to_regnum
1287 (gdbarch, cache->retaddr_reg.loc.reg);
1288 addr += get_frame_register_unsigned (this_frame, regnum);
1289 return frame_unwind_got_address (this_frame, regnum, addr);
1291 case DWARF2_FRAME_REG_FN:
1292 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1295 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1300 dwarf2_frame_sniffer (const struct frame_unwind *self,
1301 struct frame_info *this_frame, void **this_cache)
1303 /* Grab an address that is guarenteed to reside somewhere within the
1304 function. get_frame_pc(), with a no-return next function, can
1305 end up returning something past the end of this function's body.
1306 If the frame we're sniffing for is a signal frame whose start
1307 address is placed on the stack by the OS, its FDE must
1308 extend one byte before its start address or we could potentially
1309 select the FDE of the previous function. */
1310 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1311 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1316 /* On some targets, signal trampolines may have unwind information.
1317 We need to recognize them so that we set the frame type
1320 if (fde->cie->signal_frame
1321 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1323 return self->type == SIGTRAMP_FRAME;
1325 return self->type != SIGTRAMP_FRAME;
1328 static const struct frame_unwind dwarf2_frame_unwind =
1331 dwarf2_frame_unwind_stop_reason,
1332 dwarf2_frame_this_id,
1333 dwarf2_frame_prev_register,
1335 dwarf2_frame_sniffer
1338 static const struct frame_unwind dwarf2_signal_frame_unwind =
1341 dwarf2_frame_unwind_stop_reason,
1342 dwarf2_frame_this_id,
1343 dwarf2_frame_prev_register,
1345 dwarf2_frame_sniffer
1348 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1351 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1353 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1354 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1358 /* There is no explicitly defined relationship between the CFA and the
1359 location of frame's local variables and arguments/parameters.
1360 Therefore, frame base methods on this page should probably only be
1361 used as a last resort, just to avoid printing total garbage as a
1362 response to the "info frame" command. */
1365 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1367 struct dwarf2_frame_cache *cache =
1368 dwarf2_frame_cache (this_frame, this_cache);
1373 static const struct frame_base dwarf2_frame_base =
1375 &dwarf2_frame_unwind,
1376 dwarf2_frame_base_address,
1377 dwarf2_frame_base_address,
1378 dwarf2_frame_base_address
1381 const struct frame_base *
1382 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1384 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1386 if (dwarf2_frame_find_fde (&block_addr, NULL))
1387 return &dwarf2_frame_base;
1392 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1393 the DWARF unwinder. This is used to implement
1394 DW_OP_call_frame_cfa. */
1397 dwarf2_frame_cfa (struct frame_info *this_frame)
1399 while (get_frame_type (this_frame) == INLINE_FRAME)
1400 this_frame = get_prev_frame (this_frame);
1401 /* This restriction could be lifted if other unwinders are known to
1402 compute the frame base in a way compatible with the DWARF
1404 if (! frame_unwinder_is (this_frame, &dwarf2_frame_unwind))
1405 error (_("can't compute CFA for this frame"));
1406 return get_frame_base (this_frame);
1409 const struct objfile_data *dwarf2_frame_objfile_data;
1412 read_1_byte (bfd *abfd, gdb_byte *buf)
1414 return bfd_get_8 (abfd, buf);
1418 read_4_bytes (bfd *abfd, gdb_byte *buf)
1420 return bfd_get_32 (abfd, buf);
1424 read_8_bytes (bfd *abfd, gdb_byte *buf)
1426 return bfd_get_64 (abfd, buf);
1430 read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1433 unsigned int num_read;
1443 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1446 result |= ((byte & 0x7f) << shift);
1449 while (byte & 0x80);
1451 *bytes_read_ptr = num_read;
1457 read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1461 unsigned int num_read;
1470 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1473 result |= ((byte & 0x7f) << shift);
1476 while (byte & 0x80);
1478 if (shift < 8 * sizeof (result) && (byte & 0x40))
1479 result |= -(((LONGEST)1) << shift);
1481 *bytes_read_ptr = num_read;
1487 read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1491 result = bfd_get_32 (abfd, buf);
1492 if (result == 0xffffffff)
1494 result = bfd_get_64 (abfd, buf + 4);
1495 *bytes_read_ptr = 12;
1498 *bytes_read_ptr = 4;
1504 /* Pointer encoding helper functions. */
1506 /* GCC supports exception handling based on DWARF2 CFI. However, for
1507 technical reasons, it encodes addresses in its FDE's in a different
1508 way. Several "pointer encodings" are supported. The encoding
1509 that's used for a particular FDE is determined by the 'R'
1510 augmentation in the associated CIE. The argument of this
1511 augmentation is a single byte.
1513 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1514 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1515 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1516 address should be interpreted (absolute, relative to the current
1517 position in the FDE, ...). Bit 7, indicates that the address
1518 should be dereferenced. */
1521 encoding_for_size (unsigned int size)
1526 return DW_EH_PE_udata2;
1528 return DW_EH_PE_udata4;
1530 return DW_EH_PE_udata8;
1532 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1537 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1538 int ptr_len, const gdb_byte *buf,
1539 unsigned int *bytes_read_ptr,
1540 CORE_ADDR func_base)
1545 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1547 if (encoding & DW_EH_PE_indirect)
1548 internal_error (__FILE__, __LINE__,
1549 _("Unsupported encoding: DW_EH_PE_indirect"));
1551 *bytes_read_ptr = 0;
1553 switch (encoding & 0x70)
1555 case DW_EH_PE_absptr:
1558 case DW_EH_PE_pcrel:
1559 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1560 base += (buf - unit->dwarf_frame_buffer);
1562 case DW_EH_PE_datarel:
1565 case DW_EH_PE_textrel:
1568 case DW_EH_PE_funcrel:
1571 case DW_EH_PE_aligned:
1573 offset = buf - unit->dwarf_frame_buffer;
1574 if ((offset % ptr_len) != 0)
1576 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1577 buf += *bytes_read_ptr;
1581 internal_error (__FILE__, __LINE__,
1582 _("Invalid or unsupported encoding"));
1585 if ((encoding & 0x07) == 0x00)
1587 encoding |= encoding_for_size (ptr_len);
1588 if (bfd_get_sign_extend_vma (unit->abfd))
1589 encoding |= DW_EH_PE_signed;
1592 switch (encoding & 0x0f)
1594 case DW_EH_PE_uleb128:
1597 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1599 *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf;
1600 return base + value;
1602 case DW_EH_PE_udata2:
1603 *bytes_read_ptr += 2;
1604 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1605 case DW_EH_PE_udata4:
1606 *bytes_read_ptr += 4;
1607 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1608 case DW_EH_PE_udata8:
1609 *bytes_read_ptr += 8;
1610 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1611 case DW_EH_PE_sleb128:
1614 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1616 *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf;
1617 return base + value;
1619 case DW_EH_PE_sdata2:
1620 *bytes_read_ptr += 2;
1621 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1622 case DW_EH_PE_sdata4:
1623 *bytes_read_ptr += 4;
1624 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1625 case DW_EH_PE_sdata8:
1626 *bytes_read_ptr += 8;
1627 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1629 internal_error (__FILE__, __LINE__,
1630 _("Invalid or unsupported encoding"));
1636 bsearch_cie_cmp (const void *key, const void *element)
1638 ULONGEST cie_pointer = *(ULONGEST *) key;
1639 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1641 if (cie_pointer == cie->cie_pointer)
1644 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1647 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1648 static struct dwarf2_cie *
1649 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1651 struct dwarf2_cie **p_cie;
1653 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1654 bsearch be non-NULL. */
1655 if (cie_table->entries == NULL)
1657 gdb_assert (cie_table->num_entries == 0);
1661 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1662 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1668 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1670 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1672 const int n = cie_table->num_entries;
1675 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1677 cie_table->entries =
1678 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1679 cie_table->entries[n] = cie;
1680 cie_table->num_entries = n + 1;
1684 bsearch_fde_cmp (const void *key, const void *element)
1686 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1687 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1689 if (seek_pc < fde->initial_location)
1691 if (seek_pc < fde->initial_location + fde->address_range)
1696 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1697 inital location associated with it into *PC. */
1699 static struct dwarf2_fde *
1700 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1702 struct objfile *objfile;
1704 ALL_OBJFILES (objfile)
1706 struct dwarf2_fde_table *fde_table;
1707 struct dwarf2_fde **p_fde;
1711 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1712 if (fde_table == NULL)
1714 dwarf2_build_frame_info (objfile);
1715 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1717 gdb_assert (fde_table != NULL);
1719 if (fde_table->num_entries == 0)
1722 gdb_assert (objfile->section_offsets);
1723 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1725 gdb_assert (fde_table->num_entries > 0);
1726 if (*pc < offset + fde_table->entries[0]->initial_location)
1729 seek_pc = *pc - offset;
1730 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1731 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1734 *pc = (*p_fde)->initial_location + offset;
1736 *out_offset = offset;
1743 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1745 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1747 if (fde->address_range == 0)
1748 /* Discard useless FDEs. */
1751 fde_table->num_entries += 1;
1752 fde_table->entries =
1753 xrealloc (fde_table->entries,
1754 fde_table->num_entries * sizeof (fde_table->entries[0]));
1755 fde_table->entries[fde_table->num_entries - 1] = fde;
1758 #ifdef CC_HAS_LONG_LONG
1759 #define DW64_CIE_ID 0xffffffffffffffffULL
1761 #define DW64_CIE_ID ~0
1764 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1769 EH_CIE_TYPE_ID = 1 << 0,
1770 EH_FDE_TYPE_ID = 1 << 1,
1771 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1774 static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start,
1776 struct dwarf2_cie_table *cie_table,
1777 struct dwarf2_fde_table *fde_table,
1778 enum eh_frame_type entry_type);
1780 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1781 Return NULL if invalid input, otherwise the next byte to be processed. */
1784 decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1785 struct dwarf2_cie_table *cie_table,
1786 struct dwarf2_fde_table *fde_table,
1787 enum eh_frame_type entry_type)
1789 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1790 gdb_byte *buf, *end;
1792 unsigned int bytes_read;
1795 ULONGEST cie_pointer;
1798 length = read_initial_length (unit->abfd, buf, &bytes_read);
1802 /* Are we still within the section? */
1803 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1809 /* Distinguish between 32 and 64-bit encoded frame info. */
1810 dwarf64_p = (bytes_read == 12);
1812 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1816 cie_id = DW64_CIE_ID;
1822 cie_pointer = read_8_bytes (unit->abfd, buf);
1827 cie_pointer = read_4_bytes (unit->abfd, buf);
1831 if (cie_pointer == cie_id)
1833 /* This is a CIE. */
1834 struct dwarf2_cie *cie;
1836 unsigned int cie_version;
1838 /* Check that a CIE was expected. */
1839 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1840 error (_("Found a CIE when not expecting it."));
1842 /* Record the offset into the .debug_frame section of this CIE. */
1843 cie_pointer = start - unit->dwarf_frame_buffer;
1845 /* Check whether we've already read it. */
1846 if (find_cie (cie_table, cie_pointer))
1849 cie = (struct dwarf2_cie *)
1850 obstack_alloc (&unit->objfile->objfile_obstack,
1851 sizeof (struct dwarf2_cie));
1852 cie->initial_instructions = NULL;
1853 cie->cie_pointer = cie_pointer;
1855 /* The encoding for FDE's in a normal .debug_frame section
1856 depends on the target address size. */
1857 cie->encoding = DW_EH_PE_absptr;
1859 /* We'll determine the final value later, but we need to
1860 initialize it conservatively. */
1861 cie->signal_frame = 0;
1863 /* Check version number. */
1864 cie_version = read_1_byte (unit->abfd, buf);
1865 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1867 cie->version = cie_version;
1870 /* Interpret the interesting bits of the augmentation. */
1871 cie->augmentation = augmentation = (char *) buf;
1872 buf += (strlen (augmentation) + 1);
1874 /* Ignore armcc augmentations. We only use them for quirks,
1875 and that doesn't happen until later. */
1876 if (strncmp (augmentation, "armcc", 5) == 0)
1877 augmentation += strlen (augmentation);
1879 /* The GCC 2.x "eh" augmentation has a pointer immediately
1880 following the augmentation string, so it must be handled
1882 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1885 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1889 if (cie->version >= 4)
1891 /* FIXME: check that this is the same as from the CU header. */
1892 cie->addr_size = read_1_byte (unit->abfd, buf);
1894 cie->segment_size = read_1_byte (unit->abfd, buf);
1899 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1900 cie->segment_size = 0;
1902 /* Address values in .eh_frame sections are defined to have the
1903 target's pointer size. Watchout: This breaks frame info for
1904 targets with pointer size < address size, unless a .debug_frame
1905 section exists as well. */
1907 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1909 cie->ptr_size = cie->addr_size;
1911 cie->code_alignment_factor =
1912 read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1915 cie->data_alignment_factor =
1916 read_signed_leb128 (unit->abfd, buf, &bytes_read);
1919 if (cie_version == 1)
1921 cie->return_address_register = read_1_byte (unit->abfd, buf);
1925 cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
1927 cie->return_address_register
1928 = dwarf2_frame_adjust_regnum (gdbarch,
1929 cie->return_address_register,
1934 cie->saw_z_augmentation = (*augmentation == 'z');
1935 if (cie->saw_z_augmentation)
1939 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1943 cie->initial_instructions = buf + length;
1947 while (*augmentation)
1949 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1950 if (*augmentation == 'L')
1957 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1958 else if (*augmentation == 'R')
1960 cie->encoding = *buf++;
1964 /* "P" indicates a personality routine in the CIE augmentation. */
1965 else if (*augmentation == 'P')
1967 /* Skip. Avoid indirection since we throw away the result. */
1968 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
1969 read_encoded_value (unit, encoding, cie->ptr_size,
1970 buf, &bytes_read, 0);
1975 /* "S" indicates a signal frame, such that the return
1976 address must not be decremented to locate the call frame
1977 info for the previous frame; it might even be the first
1978 instruction of a function, so decrementing it would take
1979 us to a different function. */
1980 else if (*augmentation == 'S')
1982 cie->signal_frame = 1;
1986 /* Otherwise we have an unknown augmentation. Assume that either
1987 there is no augmentation data, or we saw a 'z' prefix. */
1990 if (cie->initial_instructions)
1991 buf = cie->initial_instructions;
1996 cie->initial_instructions = buf;
2000 add_cie (cie_table, cie);
2004 /* This is a FDE. */
2005 struct dwarf2_fde *fde;
2007 /* Check that an FDE was expected. */
2008 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2009 error (_("Found an FDE when not expecting it."));
2011 /* In an .eh_frame section, the CIE pointer is the delta between the
2012 address within the FDE where the CIE pointer is stored and the
2013 address of the CIE. Convert it to an offset into the .eh_frame
2017 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2018 cie_pointer -= (dwarf64_p ? 8 : 4);
2021 /* In either case, validate the result is still within the section. */
2022 if (cie_pointer >= unit->dwarf_frame_size)
2025 fde = (struct dwarf2_fde *)
2026 obstack_alloc (&unit->objfile->objfile_obstack,
2027 sizeof (struct dwarf2_fde));
2028 fde->cie = find_cie (cie_table, cie_pointer);
2029 if (fde->cie == NULL)
2031 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2032 eh_frame_p, cie_table, fde_table,
2034 fde->cie = find_cie (cie_table, cie_pointer);
2037 gdb_assert (fde->cie != NULL);
2039 fde->initial_location =
2040 read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2041 buf, &bytes_read, 0);
2044 fde->address_range =
2045 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2046 fde->cie->ptr_size, buf, &bytes_read, 0);
2049 /* A 'z' augmentation in the CIE implies the presence of an
2050 augmentation field in the FDE as well. The only thing known
2051 to be in here at present is the LSDA entry for EH. So we
2052 can skip the whole thing. */
2053 if (fde->cie->saw_z_augmentation)
2057 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
2058 buf += bytes_read + length;
2063 fde->instructions = buf;
2066 fde->eh_frame_p = eh_frame_p;
2068 add_fde (fde_table, fde);
2074 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2075 expect an FDE or a CIE. */
2078 decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
2079 struct dwarf2_cie_table *cie_table,
2080 struct dwarf2_fde_table *fde_table,
2081 enum eh_frame_type entry_type)
2083 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2085 ptrdiff_t start_offset;
2089 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2090 cie_table, fde_table, entry_type);
2094 /* We have corrupt input data of some form. */
2096 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2097 and mismatches wrt padding and alignment of debug sections. */
2098 /* Note that there is no requirement in the standard for any
2099 alignment at all in the frame unwind sections. Testing for
2100 alignment before trying to interpret data would be incorrect.
2102 However, GCC traditionally arranged for frame sections to be
2103 sized such that the FDE length and CIE fields happen to be
2104 aligned (in theory, for performance). This, unfortunately,
2105 was done with .align directives, which had the side effect of
2106 forcing the section to be aligned by the linker.
2108 This becomes a problem when you have some other producer that
2109 creates frame sections that are not as strictly aligned. That
2110 produces a hole in the frame info that gets filled by the
2113 The GCC behaviour is arguably a bug, but it's effectively now
2114 part of the ABI, so we're now stuck with it, at least at the
2115 object file level. A smart linker may decide, in the process
2116 of compressing duplicate CIE information, that it can rewrite
2117 the entire output section without this extra padding. */
2119 start_offset = start - unit->dwarf_frame_buffer;
2120 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2122 start += 4 - (start_offset & 3);
2123 workaround = ALIGN4;
2126 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2128 start += 8 - (start_offset & 7);
2129 workaround = ALIGN8;
2133 /* Nothing left to try. Arrange to return as if we've consumed
2134 the entire input section. Hopefully we'll get valid info from
2135 the other of .debug_frame/.eh_frame. */
2137 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2147 complaint (&symfile_complaints, _("\
2148 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2149 unit->dwarf_frame_section->owner->filename,
2150 unit->dwarf_frame_section->name);
2154 complaint (&symfile_complaints, _("\
2155 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2156 unit->dwarf_frame_section->owner->filename,
2157 unit->dwarf_frame_section->name);
2161 complaint (&symfile_complaints,
2162 _("Corrupt data in %s:%s"),
2163 unit->dwarf_frame_section->owner->filename,
2164 unit->dwarf_frame_section->name);
2172 qsort_fde_cmp (const void *a, const void *b)
2174 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2175 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2177 if (aa->initial_location == bb->initial_location)
2179 if (aa->address_range != bb->address_range
2180 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2181 /* Linker bug, e.g. gold/10400.
2182 Work around it by keeping stable sort order. */
2183 return (a < b) ? -1 : 1;
2185 /* Put eh_frame entries after debug_frame ones. */
2186 return aa->eh_frame_p - bb->eh_frame_p;
2189 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2193 dwarf2_build_frame_info (struct objfile *objfile)
2195 struct comp_unit *unit;
2196 gdb_byte *frame_ptr;
2197 struct dwarf2_cie_table cie_table;
2198 struct dwarf2_fde_table fde_table;
2199 struct dwarf2_fde_table *fde_table2;
2200 volatile struct gdb_exception e;
2202 cie_table.num_entries = 0;
2203 cie_table.entries = NULL;
2205 fde_table.num_entries = 0;
2206 fde_table.entries = NULL;
2208 /* Build a minimal decoding of the DWARF2 compilation unit. */
2209 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2210 sizeof (struct comp_unit));
2211 unit->abfd = objfile->obfd;
2212 unit->objfile = objfile;
2216 if (objfile->separate_debug_objfile_backlink == NULL)
2218 /* Do not read .eh_frame from separate file as they must be also
2219 present in the main file. */
2220 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2221 &unit->dwarf_frame_section,
2222 &unit->dwarf_frame_buffer,
2223 &unit->dwarf_frame_size);
2224 if (unit->dwarf_frame_size)
2226 asection *got, *txt;
2228 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2229 that is used for the i386/amd64 target, which currently is
2230 the only target in GCC that supports/uses the
2231 DW_EH_PE_datarel encoding. */
2232 got = bfd_get_section_by_name (unit->abfd, ".got");
2234 unit->dbase = got->vma;
2236 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2238 txt = bfd_get_section_by_name (unit->abfd, ".text");
2240 unit->tbase = txt->vma;
2242 TRY_CATCH (e, RETURN_MASK_ERROR)
2244 frame_ptr = unit->dwarf_frame_buffer;
2245 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2246 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2247 &cie_table, &fde_table,
2248 EH_CIE_OR_FDE_TYPE_ID);
2253 warning (_("skipping .eh_frame info of %s: %s"),
2254 objfile->name, e.message);
2256 if (fde_table.num_entries != 0)
2258 xfree (fde_table.entries);
2259 fde_table.entries = NULL;
2260 fde_table.num_entries = 0;
2262 /* The cie_table is discarded by the next if. */
2265 if (cie_table.num_entries != 0)
2267 /* Reinit cie_table: debug_frame has different CIEs. */
2268 xfree (cie_table.entries);
2269 cie_table.num_entries = 0;
2270 cie_table.entries = NULL;
2275 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2276 &unit->dwarf_frame_section,
2277 &unit->dwarf_frame_buffer,
2278 &unit->dwarf_frame_size);
2279 if (unit->dwarf_frame_size)
2281 int num_old_fde_entries = fde_table.num_entries;
2283 TRY_CATCH (e, RETURN_MASK_ERROR)
2285 frame_ptr = unit->dwarf_frame_buffer;
2286 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2287 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2288 &cie_table, &fde_table,
2289 EH_CIE_OR_FDE_TYPE_ID);
2293 warning (_("skipping .debug_frame info of %s: %s"),
2294 objfile->name, e.message);
2296 if (fde_table.num_entries != 0)
2298 fde_table.num_entries = num_old_fde_entries;
2299 if (num_old_fde_entries == 0)
2301 xfree (fde_table.entries);
2302 fde_table.entries = NULL;
2306 fde_table.entries = xrealloc (fde_table.entries,
2307 fde_table.num_entries *
2308 sizeof (fde_table.entries[0]));
2311 fde_table.num_entries = num_old_fde_entries;
2312 /* The cie_table is discarded by the next if. */
2316 /* Discard the cie_table, it is no longer needed. */
2317 if (cie_table.num_entries != 0)
2319 xfree (cie_table.entries);
2320 cie_table.entries = NULL; /* Paranoia. */
2321 cie_table.num_entries = 0; /* Paranoia. */
2324 /* Copy fde_table to obstack: it is needed at runtime. */
2325 fde_table2 = (struct dwarf2_fde_table *)
2326 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2328 if (fde_table.num_entries == 0)
2330 fde_table2->entries = NULL;
2331 fde_table2->num_entries = 0;
2335 struct dwarf2_fde *fde_prev = NULL;
2336 struct dwarf2_fde *first_non_zero_fde = NULL;
2339 /* Prepare FDE table for lookups. */
2340 qsort (fde_table.entries, fde_table.num_entries,
2341 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2343 /* Check for leftovers from --gc-sections. The GNU linker sets
2344 the relevant symbols to zero, but doesn't zero the FDE *end*
2345 ranges because there's no relocation there. It's (offset,
2346 length), not (start, end). On targets where address zero is
2347 just another valid address this can be a problem, since the
2348 FDEs appear to be non-empty in the output --- we could pick
2349 out the wrong FDE. To work around this, when overlaps are
2350 detected, we prefer FDEs that do not start at zero.
2352 Start by finding the first FDE with non-zero start. Below
2353 we'll discard all FDEs that start at zero and overlap this
2355 for (i = 0; i < fde_table.num_entries; i++)
2357 struct dwarf2_fde *fde = fde_table.entries[i];
2359 if (fde->initial_location != 0)
2361 first_non_zero_fde = fde;
2366 /* Since we'll be doing bsearch, squeeze out identical (except
2367 for eh_frame_p) fde entries so bsearch result is predictable.
2368 Also discard leftovers from --gc-sections. */
2369 fde_table2->num_entries = 0;
2370 for (i = 0; i < fde_table.num_entries; i++)
2372 struct dwarf2_fde *fde = fde_table.entries[i];
2374 if (fde->initial_location == 0
2375 && first_non_zero_fde != NULL
2376 && (first_non_zero_fde->initial_location
2377 < fde->initial_location + fde->address_range))
2380 if (fde_prev != NULL
2381 && fde_prev->initial_location == fde->initial_location)
2384 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2385 sizeof (fde_table.entries[0]));
2386 ++fde_table2->num_entries;
2389 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2391 /* Discard the original fde_table. */
2392 xfree (fde_table.entries);
2395 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2398 /* Provide a prototype to silence -Wmissing-prototypes. */
2399 void _initialize_dwarf2_frame (void);
2402 _initialize_dwarf2_frame (void)
2404 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2405 dwarf2_frame_objfile_data = register_objfile_data ();